I have a st70 series 2 also that i just picked up.the board is nasty looking as it's had problems the bias leds aren't working1 bias set screw has broke of and another pot added in that place it works , but i would like to put it back to normal and ad some of these new mods to keep it from burning up .is there anyone making the boards for these ? does anyone have a board from one and willing to sell it ?

I'm not aware of anyone other than Dynaco (Panor) that EVER made any boards for the series2.LEDs and trim pots are cheap, but using some finesse putting them in an old board may require some expertise.